Re: md does a monthly resync?? (was Re: Questions about RAID 6)
Hi, Hugo:
On Tuesday 04 May 2010 20:25:52 Hugo Vanwoerkom wrote:
> martin f krafft wrote:
> > also sprach Hugo Vanwoerkom <hvw59601@care2.com> [2010.05.04.1808 +0200]:
> >> I forget your specifics, but you do RAID *and* backup regularly to an
> >> external lvm2?
> >
> > RAID is not a backup solution, it's an availability measure.
>
> But as data availability goes up by using RAID doesn't the need for
> backing up that same data go down? Or is this just semantics?
No, it isn't. While avaliability relates to a quantitative concept (how much
time, out of the total, will this system be online?), backup relates to a
qualitative concept (it either works, in which case I don't need the backup
at all, or it doesn't work in which case I need the backup, no excuses).
Rising avaliability means that you'll need your backups (say) once every ten
years instead of once a year. But when you need them, there's no option: you
need them.
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